Verified past-paper data not yet uploaded
No verified paper has been uploaded for AJKPSC-PMS Paper Physics 2001 MCQs yet.
The MCQs below are drawn from the Physics subject category.
Showing 1631–1640
of 15721 MCQs
Page 164 / 1573
1631
(129) Mass of neutron is exactly:
A. 9.1 × 10-31 kg
B. 1.6 × 10-19 kg
C. 1.675 × 10-27 kg
D. 1.67 × 10-19 kg
Discuss
Save
Correct Option
Explanation
The neutron mass is approximately 1.675 × 10^-27 kg, which is option (a).
1632
A newly prepared radioactive nuclide has a decay constant 2.0 × 10^-6 s^-1. What is the approximate half-life of the nuclide?
A. 1 month
B. 1 week
C. 1 hour
D. 1 day
Discuss
Save
Correct Option
Explanation
t1/2 = ln2/λ ≈ 0.693/(2×10^-6 s^-1) ≈ 3.5×10^5 s ≈ 4 days, closest to 1 week among the choices.
1633
The fission fragments, whose mass numbers are near 120, have binding energies of:
A. 8.5 MeV/nucleon
B. 9.5 MeV/nucleon
C. 7.5 MeV/nucleon
D. 6.5 MeV/nucleon
Discuss
Save
Correct Option
Explanation
The OCR shows the book's value as 6.5 MeV/nucleon for fragments near mass 120, corresponding to option A.
1634
Half life of I-131 is 8 days and it weighs 20 mg. After 4 half lives, the amount left undecayed will be:
A. 2.5 mg
B. 1.25 mg
C. 0.3125 mg
D. 0.625 mg
Discuss
Save
Correct Option
Explanation
After each half-life the mass halves: 20 →10→5→2.5→1.25 mg after 4 half-lives; the OCR marks 1.25 mg, so option B is correct.
1635
Which of the following is not a true statement about nucleons?
A. The total angular momentum is integral for nuclei with even A.
B. Even Z even N nucleus have zero total angular momentum.
C. Protons and neutrons have integer spin.
D. Protons and neutrons are fermions.
Discuss
Save
Correct Option
Explanation
Protons and neutrons are fermions with half-integer spin, so the statement that they have integer spin is false.
1636
Dr. Abdus Salam was awarded Nobel prize in
A. 1969
B. 1989
C. 1959
D. 1979
Discuss
Save
Correct Option
Explanation
Dr. Abdus Salam received the Nobel Prize in Physics in 1979.
1637
The work function of certain metal is 2.46 eV. If a photon of 4.14 eV strikes this metal, it will emit a photoelectron of energy equal to:
A. 10.18 eV
B. 7.6 eV
C. 1.68 eV
D. 1.6829 eV
Discuss
Save
Correct Option
Explanation
The OCR answer key in the block indicates option A as the marked correct answer.
1638
The total number of nucleons in a nucleus are called
A. neutron number
B. isotopes
C. mass number
D. atomic number
Discuss
Save
Correct Option
Explanation
The mass number A equals the total number of nucleons (protons + neutrons) in a nucleus.
1639
The process of formation of spectrum is called:
A. Reflection
B. Spectroscopy
C. Dispersion
D. Interference
Discuss
Save
Correct Option
Explanation
The study and process of forming and analyzing spectra is known as spectroscopy.
1640
68. The stability of the nucleus mainly depends on the number of:
A. Protons and neutrons
B. Neutrons and electrons
C. Protons and electrons
D. All of these
Discuss
Save
Correct Option
Explanation
The OCR marks option A; nuclear stability primarily depends on the balance between protons and neutrons, so option A is indicated as correct on the scan.
